I'm working through "Building Walking Bass Lines" by Ed Friedland (big thumbs up). I'm nearly through part one, and while I can't say the bass lines I create sound as good as the ones Ed provides as samples, I'm understanding it and am making definite progress. Last night I took a look at the exercise on using the scale tones as approach notes. Problem is, I don't understand WHAT scale to use. I kind of assume if I'm playing blues in B flat, I'd use the B flat major scale more or less regardless of what the chord is. That's based on the idea that the chord also contains notes that are in the B flat scale (I know just enough to know that this probably isn't true for modal music, but I'm willing to ignore that for now). Is this correct or am I way off?